Stop devices for well conduits



April 1, 1958 .1. c; coMs'rocK 2,828,824

STOP DEVICES FOR WELL CONDUITS Filed Jan. 20, 1955 2 Sheets-Sheet 1 l 1; 12 rlbH/v C. fio/wsrocz,

INVENTOR.

ATTOQNEYS April 1, 1958 J. c. coMsTocK STOP DEVICES FOR WELL CONDUITS 2 Sheets-Sheet 2 Filed Jan. 20, 1955 HO-HN C. Co/wsrock,

INVENTORL ATi-OENEYS I a r 2,828,824 1C6 Patented Apr. 1, 1958 sror DEVICES non WELL CONDUITS John C. Comstock, Houston, Tex., assignor to Baker Oil Tools, 11163., Los Angeles, Calif., a corporation of California Application January 20, 1955, Serial No. 482,959

9 Claims. (Cl. 166-243) The present invention relates to subsurface well equipment, and more particularly to devices capable of being mounted on well casing, liner, tubing, and similar conduit strings, for moving apparatus mounted on said strings longitudinally through the well bore.

Apparatus, such as casing centralizers, wall scratchers, and cement baskets, are mounted on casing, or similar conduit strings, being movable longitudinally through the well bore with the casing string because of their engagement with one or more stop devices secured to the latter. Heretofore, the stop device or devices have been secured to the casing string in a rigid manner by using welding material, which is a time consuming operation, and which also requires the availability of welding equipment at the well location. In addition, certain types of well casing do not have good weldability characteristics, making it difiicult to properly weld the stop device thereto. Moreover, Welding, particularly on certain types of alloy steel casing, may seriously weaken the casing structure through alteration of its physical properties.

Anobject of the present invention is to provide an improved stop device of the character mentioned above which can be easily and securely mounted on the conduit string without resort to welding operations and the like.

Another object of the invention is to provide a stop device of simple construction and small number of parts, which automatically secures itself on the well conduit string when in use, thereby precluding its inadvertent disconnection from the conduit string.

A further object of the invention is to provide a stop device of the type indicated which can be mounted on a well casing very easily merely by placing it laterally around the casing, thereby avoiding the necessity for disconnecting, or otherwise disturbing, casing couplings, and similar connections, at the ends of the casing section on which the stop device is to be mounted.

This invention possesses many other advantages, and has other objects, which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a side elevation of apparatus mounted on a string of well casing disposed in a well bore, parts being broken away for purposes of clarity.

Fig. 2 is an enlarged longitudinal section through a stop deviceforming part of the apparatus shown in Fig. 1;

Fig. 3 is an isometric projection of the segmental or sec- Fig. Sis

an enlarged fragmenarysection disclosing the stop device in a neutral position with respect to the well, casing;

Fig. 6 is a view similar to Fig. 5, disclosing the coupling of the stop device to the well casing when the latter tends to move upwardly;

Fig. 7 is a view similar to Fig. 5, disclosing the operation of the stop device when the well casing tends to move downwardly in the well bore.

The specific device disclosed in the drawings is used for moving a casing centralizer A mounted on a string of well casing B, or other running-in string, through a well bore C with the running-in string. It is to be understood, however, that such devices are also useful in other relationships, being adapted for engagement with wall scratchers, cementing baskets, and other apparatus mounted on a casing, or similar conduit string, to be moved longitudinally through the well bore with such conduit string, as well as being supported on the latter. 7

As shown in the drawings, the casing centralizer A is mounted on a .casing section 10 disposed in a well bore C. The centralizer can take any desired form, the one particularly shown including upper and lower longitudinally spaced collars 11, 12 slidable on the casing section 10, which are interconnected by circumferentially spaced,

outwardly bowed leaf spring members 13 welded, or

otherwise suitably secured, to the upper and lower collars. The springs 13 engage the wall of the well bore C and tend to center the well casing therewithin.

Upper and lower stop rings 14, 15 are secured in 1ongitudinally spaced relation to the upper and lower collars 11, 12, respectively, as by use of circumferentially spaced and longitudinally extending rigid bars 16 that are at: tached to both the collars 11, 12 and the rings 14, 15 in any suitable manner, as by a welding operation.

The particular centralizer disclosed is of the hinge type, in which the collars 11, 12 and the rings 14, 15 are each formed of two parts that are secured to one another by diametrically opposed hinges 17. The hinges on one side of the device may be disconnected as by removing the hinge pins 19, which then allow the casing centralizer to be swung to open position and placed laterally around the casing section 10, whereupon the centralizer can be closed and the pins 19 reinserted through the hinge knuckles 20, all in a known manner.

The centralizer or centering apparatus A is movable longitudinally through the well bore upon longitudinal movement of the casing B. A stop device D is secured to the casing section 10 between the upper and lower stop rings or collars 14, 15, such device being engageable with the inner edges 21, 22 of the rings to force the centralizer apparatus through the well bore. For example, the stop device is engageable with the upper edge 22 of the lower stop ring 15 when the casing B is moved downwardly in the well bore, to pull the apparatus A and its outwardly bowed springs 13 through the well bore and past any restrictions that might be encountered therein. Conversely, movement of the casing string in an upward direction will cause the stop device D to engage the lower edge 21 of the upper stop ring 14 and pull the centering device A in an upward direction with the casing string B within the well bore.

The particular stop device D disclosed in the drawings is designed to engage the centralizer stop rings 14, 15, the force transmitted therebetween tending to more firmly secure the stop device to the well casing. The stop device includes a split or segmental ring 30, which is specifically disclosed as being made of two like parts 31, 32 to facilitate the lateral or transverse placing of the ring around the casing section 10, and between the upper and lower stop rings 14, 15 of the casing centralizer A. Thus, each ring segment 31, 32 is greater than degrees in arcuate extent, including a longitudinally --ex-' tending tongue 33 and adjacent longitudinal groove 34 at I each end. The tongues 33 only extend partially along the whole length of the ring section and are adapted to fit into grooves 34 in the other ring section or segment. In effect, the segments 31, 32 are identical, except that one segment is inverted with respect to the other segment, the tongues 33 of one segment fitting into the grooves 34 of the other segment, with the tongues facing in opposite directions and being disposed adjacent one another and interlocked with each other. The same interlocking tongue and groove arrangement is provided at diametrically opposite portions of the segmental ring 30, as is evident from Fig. 3.

When the two segments 31, 32 are placed around the casing section 10 and their tongues 33 disposed in the respective grooves 34, the segments are prevented from coming apart when a lateral outward force is imposed thereon, in view of the interlocking tongues 33.

The segmental ring 30 has a larger internal diameter than the outside diameter of the casing section 19 on which it is mounted, but it is adapted to be coupled to this casing section. The ring may have an internal groove 35 provided on its interior and extending around the entire circumference of the ring. The groove 35 preferably is disposed midway along the longitudinal extent of the ring. Disposed to one side of the interlocking tongues and grooves of the segments are a pair of opposite slots 36 extending arcuately to a small extent around the ring 30 and opening inwardly into the internal groove 35. These slots or openings 36 are provided to admit of the insertion of gripping elements 37 into the groove 35 and between the ring 30 and the casing 10 after the ring has been mounted on the casing, with the segments 31, 32 interlocked with one another.

As specifically shown, the internal groove 35 includes a base surface 38 substantially parallel to the periphery of the casing 10, and upper and lower sides 39, 40' which diverge in an inward direction with respect to each other. Each gripping element 37 actually constitutes part of a spring steel rod, the gripping member being adapted to be disposed in the groove 35 and having its inner portion 41 adapted to dig into the Outer surface of the casing section 10. Specifically, the gripping member or rod has an outer surface 42 conforming in shape to the base 38 of the groove, with side members 43, 44 conforming to the sides of the groove, and diverging in an inward direction with respect to the outer surface 42 of the gripping element. The remaining two sides 45, 46 of the gripping element converge toward each other, meeting at a tooth or edge 41 that is adapted to embed itself into the peripheral portion of the casing section 10.

In the specific design of stop device shown in the drawings, two spring steel rod sections 37 are used, each section being of a length as to extend a little less than 180 degrees around the ring 30 when disposed in the internal groove 35 of the latter. After the segmental ring 30 is placed around the casing section 10 between the stop rings 14, 15 and the tongues 33 interlocked with respect to one another, a gripping element 37, which may then be of comparatively straight form, is inserted through one slot or opening 36, being fed within the internal groove 35, the rod curving around the groove to conform to the circular curvature of the ring 30, and with its outer flat side 42 and divergent side 43, 44 being disposed in the groove 35, and its inner gripping tooth or corner 41 frictionally engaging the periphery of the well casing 10. The rod 37 is inserted in the groove 35 to the extent at which it overlaps the tongue and groove portions 33, 34 of adjacent segmental members oi the ring. In the same manner, a second rod 37 is inserted through the other slot 36, being fed around the groove 35 and being disposed therein until it overlaps the opposite set of interlocking tongues and grooves with its outer side 42 and tapered sides 43, 44 disposed in the groove, and its sharp corner 41 engaging the periphery of the well casing.

When both gripping member segments 37 have been disposed in the groove 35, the stop ring 30 will be retained in a substantial coaxial position relative to the casing section 19, the inner surface of the ring being spaced from the periphery of the casing. When the stop ring 39 is disposed in such coaxial position, it will be noted that the base 38 of the groove is disposed a radial distance R from the periphery of the well casing 107 However, the distance S from the inner corner 41 of a gripping element 3'7 and the point of intersection 48 between the base 38 of the groove and an inner side 39 or 49 of the groove is substantially greater than the radial distance R. Inasmuch as the gripping element 37 fits within the groove 35 without too much clearance, the distance S from the inner corner 41 of the element and the point of intersection between the outer surface 42 of the element and each of its tapered sides 43, 44 is substantially greater than the radial distance R from the inner corner 41 of the element to the outer surface 42 of the element.

The foregoing relationship of distances becomes important in connection with the operation of the device, inasmuch as any tendency for the casing 19 and segmental ring St? to move longitudinally with respect to each other will cause a rocking of each gripping element 3'1 and its embedding in the well casing, being forced against the sides 39, ill and bottom 38 of the groove 33, to effectively lock the segmental ring 36 to the well casing.

The centralizer A is mounted on a casing section 10, after which the two parts 31, 32 of the se rnental ring 30 are disposed laterally around the casing between the stop rings 14, 15 of the centralizer, and the tongues 33 interlocked. The flexible spring steel rods or Wires 37 are then inserted in place within the ring 38 in the abovedescribed manner to couple the ring to the casing B against movement in both longitudinal directions.

The casing is then lowered in the well bore. During such lowering movement, the lower edge 49 of the segmental stop ring 30 will engage the lower ring 15 of the casing centralizer. Inasmuch as the outwardly bowed leaf springs 13 of the centralizer frictionally engage the wall of the well bore, they will tend to resist downward movement of the centralizer therewithin. As a result, during downward movement of the casing in the well bore, the centralizer will engage the segmental ring 30 of the stop device and tend to urge the ring 30 in an upward direction relative to the well casing 10 (as shown in Fig. 7). Such upward movement will, in effect, rock the gripping elements 37 on the periphery of the well casing, causing the lower corner 51 of each element to engage the lower side 40 of the groove and the lower point of intersection 48 between the lower side 44 and the outer side 42 to move upwardly in the groove and engage the base 38 of the latter. This rocking action results in the base 38 of the groove bearing against the ring 37 and urging its inner edge or tooth 41 more firmly into the casing, inasmuch as the distance S across the ring is substantially greater than the distance between the base 38 of the groove and the periphery of the casing 10. Effectively, the ring 37 then becomes wedged or locked between the casing 10, on the one hand, and the lower side 40 and base 38 of the groove, on the other hand, thereby securing the ring 30 to the casing and requiring the latter to move downwardly with the casing. Such downward movement will cause the ring 30 to engage the lower stop element 15 of the centralizer and pull the centralizer downwardly with the casing.

In the event the casing 10 is elevated in the well bore C, the segmental ring 30 of the stop device will engage the upper stop member 14 of the casing centralizer, the

upward movement of the casing being accompanied by a a reactive movement of the stop ring 30 in a relative downward direction, because of the resistance to upward movement afforded by'the centralizer springs 13 bearing against the wall of the well bore. When this occurs, the

- new;

gripping elements 37 are rocked in the opposite direction, the upper corner 55' of the ring being engaged with the upper side 39 of the groove and the upper outer corner 56 bearing against the base 38 of the groove. Such action causes the base 38 and upper side 39 of the groove 35 to force the inner corner 41 of each gripping element more firmly against the casing. Of course, the lower outer corner 48 will also engage the lower side 40 and tend to wedge the inner corner more firmly into the easing. In this manner, the segmental ring 30 is secured to the casing and is caused to move upwardly therewith, moving the centralizer in an upward direction with the well casing.

It is, therefore, apparent that a stop device for moving elements mounted on a well casing through a well bore with the casing has been provided, that is relatively simple and which can be firmly secured to the well casing against relative movement in both directions without the necessity for Welding any parts on the well casing. The stop device is easily mounted on the casing without regard to the type of couplings or other connections at the ends of a casing section. It is merely necessary to interlock the ring segments 31, 32 with respect to each other, and then force the flexible gripper elements or wires 37 through the slotted openings 36 into the grooves 35 and between the stop device ring 30 and the well casing 10. The force required to pull the centralizer device A, or other device, mounted on the well casing through the well bore C will automatically increase the coupling action of the gripper elements 37 in firmly securing the segmental ring 30 to the well casing.

The inventor claims:

1. In a stop device adapted to be mounted on a runningin string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein; a flexi ble metallic gripping element disposed in said groove, arcuately around said member, with an outer portion thereof contacting the wall of said groove, said element being adapted to rock in said groove, said element being provided with an inner edge defined by intersecting sides of said element which are inclined to the axis of said member, said inner edge extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said edge and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and the running-in string, whereby relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said edge further into engagement with the running-in string.

2. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein; a flexible metallic gripping element disposed in said groove, arcuately around said member, with an outer portion thereof contacting the wall of said groove, said element being adapted to rock in said groove, said element being provided with an inner gripping portion extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said inner gripping portion and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and the running-in string, whereby relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said inner gripping portion more firmly into engagement with the running-in string.

3. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein; a flexible metallic gripping element disposed in said groove, arcuately around said member, with an outer portion thereof contacting the wall of said groove, said element being rockably mounted in said groove, said element being provided with an inner edge defined by intersecting sides of said element which are inclined to the axis of said member, said inner edge extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said edge and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and the running-in string, whereby relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said edge fur ther into engagement with the running-in string; said annular member having an opening from its exterior into said groove through which said gripping element is insertable into said groove.

4. In a stop device adapted to be mounted on a run ning-in string to be lowered in a well bore: an annular member adapted to 'be disposed on the running-in string and having an internal circumferential groove therein; a flexible metallic gripping element disposed in said groove, arcuately around said member, with an outer portion thereof contacting the Wall of said groove, said element being adapted to rock in said groove, said element being provided with an inner gripping portion extending beyond the inner surface of said annular memher and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said inner gripping portion and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and thevrunning-in string, whereby relative longitudinaI movement in one direction between said member and running-in string will rock said element in said groove and urge said inner gripping. portion more firmly into engagement with the running-in string; said annular member having an opening from its exterior into said groove through which said gripping element is insertable into said groove.

5. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: a split annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein; means for securing together the portions of. said member on opposite sides of said member split; a flexible metallic gripping element disposed in said groove, arcuately around said member and extending across the split portion of said member, with an outer portion thereof contacting the wall of said groove, said element being adapted to rock in said groove, said element being provided with an inner gripping portion extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said inner gripping portion and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and the running-in string, whereby relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said inner gripping portion more firmly into engagement with the running-in string.

6. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: a split annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein; means for securing together the portions of said member on opposite sides of said member split; a flexible metallic gripping element disposed in said groove, arcuately around said member and extending across the split portion ofsaid member, with an outer portion thereof contacting the wall of said groove, said element being adapted to rock in said groove, said element being provided with an inner gripping portion extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the external periphery of the running-in string; the distance between said inner gripping portion and the point of contact of said element with the wall of said groove being greater than the radial distance between said point of contact and the running-in string, where- 'by relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said inner gripping portion more firmly into engagement with the running-in string; said member having an opening spaced from its split portion and extending from its exterior into said groove, said element being insertable through said opening into said groove.

7. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein, said groove being defined by a base and divergent side walls; a flexible metallic gripping element disposed in said groove, arcuately around said member, said element being provided with an inner edge extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the running-in string, said element having an outer surface adjacent said base and divergent sides companion to and adjacent said side walls to provide outer edges adapted to engage and grip said base; the distance between said inner edge and each of said outer edges being greater than the radial distance between said base and the running-in string, whereby relative longitudinal movement in one direction between said member and runningin string will rock said element in said groove and urge said inner edge further into engagement with the running-in string.

8. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore:- an annular member adapted to be disposed on the running-in string and having an internal circumferential groove therein, said groove being defined by a base and divergent side walls; a flexible metallic gripping element disposed in said groove, arcuately around said member, said element being provided with an inner edge extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the running-in string, said element having an outer surface adjacent said base and divergent sides companion to and adjacent said side walls to provide outer edges adapted to engage and grip said base; the distance between said inner edge and each of said outer edges being greater than the radial distance between said base and the running-in string, whereby relative longitudinal movement in one direction between said member and runningin string will rock said element in said groove and urge said inner edge further into engagement with the running-in string; said annular member having an opening from its exterior into said groove through which said gripping element is insertable into said groove.

9. In a stop device adapted to be mounted on a running-in string to be lowered in a well bore: a split annular member adapted to be disposed on the runningin string and having an internal circumferential groove therein; means for securing together the portions of said member on opposite sides of said member split; said groove being defined by a base and divergent side walls; a flexible metallic gripping element disposed in said groove, arcuately around said member, said element being provided with an inner edge extending beyond the inner surface of said annular member and projecting from said groove and adapted to engage and grip the running-in string, said element having an outer surface adjacent said base and divergent sides companion to and adjacent said side walls to provide outer edges adapted to engage and grip said base; the distance between said inner edge and each of said outer edges being greater than the radial distance between said base and the running-in string, whereby relative longitudinal movement in one direction between said member and running-in string will rock said element in said groove and urge said inner edge further into engagement with the running-in string; said member having an opening spaced from its split portion and extending from its exterior into said groove; said element being insertable through said opening into said groove.

References Cited in the file of this patent UNITED STATES PATENTS 331,522 Meese Dec. 1, 1885 1,201,706 Dodge Oct. 17, 1916 2,013,660 Lauer Sept. 10, 1935 2,017,994 Spang Oct. 22, 1935 2,597,482 Harrison et al. May 20, 1952 2,718,266 Berry et al. Sept. 20, 1955 FOREIGN PATENTS 7 698,464 Great Britain Oct. 14, 1953 

